/**
 * Copyright 2011 The Apache Software Foundation
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.util;

import java.util.concurrent.TimeUnit;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class RetryCounter {
	private static final Log LOG = LogFactory.getLog(RetryCounter.class);
	private final int maxRetries;
	private int retriesRemaining;
	private final int retryIntervalMillis;
	private final TimeUnit timeUnit;

	public RetryCounter(int maxRetries, int retryIntervalMillis, TimeUnit timeUnit) {
		this.maxRetries = maxRetries;
		this.retriesRemaining = maxRetries;
		this.retryIntervalMillis = retryIntervalMillis;
		this.timeUnit = timeUnit;
	}

	public int getMaxRetries() {
		return maxRetries;
	}

	/**
	 * Sleep for a exponentially back off time
	 * @throws InterruptedException
	 */
	public void sleepUntilNextRetry() throws InterruptedException {
		int attempts = getAttemptTimes();
		long sleepTime = (long) (retryIntervalMillis * Math.pow(2, attempts));
		LOG.info("Sleeping " + sleepTime + "ms before retry #" + attempts + "...");
		timeUnit.sleep(sleepTime);
	}

	public boolean shouldRetry() {
		return retriesRemaining > 0;
	}

	public void useRetry() {
		retriesRemaining--;
	}

	public int getAttemptTimes() {
		return maxRetries - retriesRemaining + 1;
	}
}
